What are the other Names for this Condition? (Also known as/Synonyms)

• Laryngeal SFT
• Laryngeal Solitary Fibrous Tumor
• SFT of Larynx

What is Solitary Fibrous Tumor of Larynx? (Definition/Background Information)

• Solitary Fibrous Tumor (SFT) of Larynx is a mostly benign (non-cancerous) overgrowth arising from mesenchymal tissue
• The mesenchyme is the middle layer of the 3 primary germ layers of an embryo, namely the ectoderm, mesoderm, and endoderm. The mesoderm gives rise to mesenchymal tissue, which is the source for bone, muscle, connective tissue, and dermis of skin
• Solitary Fibrous Tumors are composed of fibroblasts and related cell types. These rare tumors can occur in any part of the body, or in the soft tissues, where mesenchymal cells are present. The tumor arises in the larynx as a mass
• The cause of formation of the tumor is unknown and currently, no known methods exist to prevent occurrence of the tumor
• Most small tumors are asymptomatic, though the larger ones may compress the surrounding structures and cause related signs and symptoms. The diagnosis of Solitary Fibrous Tumor of Larynx can be confirmed through a tissue biopsy
• The treatment is complete surgical removal of the tumor with adequate margins. Most Solitary Fibrous Tumors of Larynx are benign, however some show malignant behavior in terms of recurrence of the tumor after surgery, or metastasis (spread to distant parts of the body)
• The prognosis of Solitary Fibrous Tumor of Larynx is dependent on whether the tumor can be completely removed through surgery or not

Who gets Solitary Fibrous Tumor of Larynx? (Age and Sex Distribution)

• Solitary Fibrous Tumor of Larynx can be present in individuals between 20 and 70 years of age, but is usually diagnosed in the fifth decade (between 40-50 years)
• In general, both men and women can get it
• Though it is a rare tumor, it can occur worldwide and all races and ethnic groups may be affected

What are the Risk Factors for Solitary Fibrous Tumor of Larynx? (Predisposing Factors)

• No clear-cut risk factors for Solitary Fibrous Tumor of Larynx have been established to date

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Solitary Fibrous Tumor of Larynx? (Etiology)

• Currently, scientists do not know the factor(s) causing Solitary Fibrous Tumor of Larynx
• Certain genetic mutations are have been detected. Research to characterize these mutations is currently underway

What are the Signs and Symptoms of Solitary Fibrous Tumor of Larynx?

The signs and symptoms depend on the size of the tumor. Solitary Fibrous Tumors can range in size from a few cm to up to 40 cm; though majority of the laryngeal tumors are less than 10 cm. They are usually slow-growing and form a single mass. The signs and symptoms associated with Solitary Fibrous Tumor of Larynx include:

• Small tumors usually do not cause any symptoms. But, occasionally they may become painful, if they compress surrounding structure
• The tumor may be present as a slowly enlarging painless mass
• Hoarseness of voice
• Voice loss
• Tickling sensation in throat
• Sensation of a lump in the throat
• Dry throat and sore throat
• Dry cough
• Voice fatigue
• Decreased pitch range
• Shooting pain that is experienced from ear to ear
• Rarely, these tumors, especially if large, may cause hypoglycemia
  • Hypoglycemia results in Doege-Potter syndrome, which occurs due to secretion of insulin-like growth factor-2 (IGF-2) by the tumor cells (paraneoplastic syndrome)
  • The signs and symptoms of hypoglycemia include confusion, altered mental status, sweating, dizziness, cold hands, etc.

How is Solitary Fibrous Tumor of Larynx Diagnosed?

The following procedures and tools may be used in the diagnosis of Solitary Fibrous Tumor of Larynx:

• Evaluation of the individual’s medical history and a through physical examination
• Individuals with the tumor may be referred to an ear, nose, and throat (ENT) physician (otolaryngologist) to further examine the vocal cords and upper airway
• Laryngoscopy: Examination of the vocal cords using a light and tiny mirror, to visually examine the throat
• Plain X-ray of the neck
• CT scan with contrast of the Head and Neck usually shows a well-defined mass which may have calcifications
• MRI scan of head and neck
• Ultrasound scan of neck
• Solitary Fibrous Tumor of Larynx can additionally be evaluated using angiography of the abdomen region
• MRI scans and PET scans may help to differentiate between benign versus malignant Solitary Fibrous Tumor of Larynx by detecting areas of metastasis (if any)

Although the above modalities can be used to make an initial diagnosis, a tissue biopsy of the tumor is necessary to make a definitive diagnosis to begin treatment. The tissue for diagnosis can be procured in multiple different ways which include: 

• Fine needle aspiration (FNA) biopsy of the tumor: A FNA biopsy may not be helpful, because one may not be able to visualize the different morphological areas of the tumor. Hence, a FNA biopsy as a diagnostic tool has certain limitations, and an open surgical biopsy is preferred. Also, Solitary Fibrous Tumor is a fibrous tumor and FNA usually does not reveal many cells on microscopic examination
• Core biopsy of the tumor
• Open biopsy of the tumor

Tissue biopsy:

• A tissue biopsy of the tumor is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis
• Biopsy specimens are studied initially using Hematoxylin and Eosin staining. The pathologist then decides on additional studies depending on the clinical situation
• Sometimes, the pathologist may perform special studies, which may include immunohistochemical stains, molecular testing, and very rarely, electron microscopic studies to assist in the diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Solitary Fibrous Tumor of Larynx?

Complications due to Solitary Fibrous Tumor of Larynx could include:

• Changes in an individual’s voice
• If an individual uses their voice as a means for a career or living, like singers, broadcasters, attorneys, it can affect their career (and earning potential)
• In rare cases, respiratory distress may occur that requires urgent medical care
• Hypoglycemia resulting in Doege-Potter syndrome, which occurs due to secretion of insulin-like growth factor-2 (IGF-2) by the tumor cells
• Recurrence of SFT following surgery
• Malignant transformation resulting in metastatic SFT
• Complications may arise during chemotherapy and radiation therapy, due to the toxic medication or radiation effect

How is Solitary Fibrous Tumor of Larynx Treated?

There is no standard treatment protocol established for Solitary Fibrous Tumor of Larynx. However, in majority of cases, a complete surgical excision with clear or wide margins is the preferred mode of treatment, which can result in a cure, especially if it behaves in a benign manner.

The possible treatment measures for Solitary Fibrous Tumor of Larynx include the following:

• Larynx removal (laryngectomy) may be necessary in some individuals. It is a surgical procedure that involves the removal of the larynx (voice box) within the throat
• Long-term follow-up is required, because recurrence at the site of surgery or metastasis in distant sites have been reported many years after surgery, even with tumors that behave benignly
• Radiotherapy can be used as primary therapy in situations where the tumor cannot be removed completely, or when the tumor reappears (recurrent Solitary Fibrous Tumor of Larynx) after surgery
• Radiotherapy for SFT can also be used as additional therapy after surgery, if there is a possibility of tumor recurrence after surgery, or if there are inadequate margins (possibility of tumor left behind) following surgery. In some cases due to location of tumor, a complete surgical removal of the tumor is difficult
• Chemotherapy can be used for treating Solitary Fibrous Tumor of Larynx in following conditions:
  • When the tumors cannot be removed completely (due to incomplete surgical resection)
  • Tumors that recur after surgery (recurrent SFT of Larynx)
  • Tumors that have spread to distant parts of the body (metastatic SFT of Larynx)
• Arterial embolization of Solitary Fibrous Tumor of Larynx is a possible treatment option. Here the blood supply to the tumor is blocked resulting in tumor death
• Hypoglycemia due to the tumor is treated using corticosteroids
• Post-operative care is important: One must maintain minimum activity levels, until the surgical wound heals

How can Solitary Fibrous Tumor of Larynx be Prevented?

• Current medical research has not established a way of preventing Solitary Fibrous Tumor of Larynx formation
• Regular medical screening at periodic intervals with blood tests, radiological scans, and physical examinations, for those who have already endured the tumor, are helpful

What is the Prognosis of Solitary Fibrous Tumor of Larynx? (Outcomes/Resolutions)

• The most reliable prognostic factor of Solitary Fibrous Tumor of Larynx is dependent on whether the tumor can be completely removed through surgery with free margins (no traces of the tumor in adjoining tissue) or not
• Current studies show that the tumor does not have any specific histologic feature (when a pathologist examines the tissue under a microscope), which can help in assessing a definite prognosis for the tumor
• Individuals have an overall excellent survival rate following first complete surgical resection
• Solitary Fibrous Tumor of Larynx that behave malignantly can lead to death
• As with any tumor, it is important to have follow-up appointments with a physician to monitor for any returning tumors

The prognosis of Solitary Fibrous Tumors also depends upon a set of several factors, which include:

• Stage of tumor: With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor
• The surgical respectability of the tumor (meaning, if the tumor can be removed completely) 
• Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
• Age of the individual: Older individuals generally have poorer prognosis than younger individuals
• Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have worse prognosis compared to tumors that do not recur
• Response to treatment: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment

An early diagnosis and prompt treatment of the tumor generally yields better outcomes than a late diagnosis and delayed treatment.

Additional and Relevant Useful Information for Solitary Fibrous Tumor of Larynx:

• A tumor is an abnormal growth of tissue arising due to uncontrolled and rapid multiplication of cells that serve no function. They are also called neoplasms. Tumors can be benign or cancerous. A benign tumor may generally indicate no threat to one’s health; it also means that it is not “cancerous”
• Grossly, Solitary Fibrous Tumor of Larynx is well-circumscribed but not encapsulated, and on cross-section appears gray white to yellow white in color
• Microscopically, benign SFT exhibit alternation of hyper- and hypo- cellular areas, patternless pattern, keloid type collagen, and staghorn-shaped vessels-like areas
• A pathologist may use special studies such as special stains. Special stains (markers) used on biopsy samples may include CD34, CD99, Vimentin, BCL-2. These stains help differentiate Solitary Fibrous Tumors of Larynx from other benign or cancer lesions
• Although Solitary Fibrous Tumor can be classified as malignant based on the biopsy study (tumor greater than 5 cm, increased mitotic rate, necrosis, increased cellularity, or cytologic atypia, infiltrative growth, and weak CD34), these features cannot be absolutely correlated with regards to how it behaves, the nature of which may be aggressive, metastasis, or recurrent
• Basic fibroblast growth factor (bFGF) labeling index and Ki-67 labeling index can be used for evaluation of benign versus malignant Solitary Fibrous Tumors of Larynx
• Hemangiopericytoma (also known as Solitary Fibrous Tumor - Hemangiopericytoma type; or Cellular Solitary Fibrous Tumor) is closely related to SFT of Larynx, but is not identical to it. Many pathologists consider hemangiopericytoma and Solitary Fibrous Tumor as a continuum of tumors